The flooring can be laid on most types of substrate flooring which is clean, dry and level, e.g. sand and cement screed, timber flooring boards, chipboards, ply etc. Professional flooring contractor will check the site condition prior the installation. It is vital to check the moisture content of the concrete/screed. Then screed must be levelled to a tolerance of no more than a 3mm gap.
If installing a new timber flooring on existing floor boards make sure that old floorboards are secure and then its recommended you lay the new flooring opposite direction to a existing floor to stabilise any subsequent movement within either timber.
